The eyelids are important to over-all ocular health because they protect the eyes from dangers such as approaching objects or from airborne contaminants, such as pollen, dust particles or other foreign bodies. The eyelids contain several glands including the lacrimal glands and meibomian glands that produce layers of tear film that are critical for healthy eyes. When an individual blinks, a new tear film is created and tears are distributed across the cornea to lubricate the surface of the eye. This blinking action also “flushes” foreign materials from the eye.
The eyelids, however, are subject to certain problems, which while common, are none-the-less bothersome, especially for contact lens wearers, and may lead to other, more serious complications. One complication is staphylococcal blepharitis (blepharitis). Blepharitis is a common chronic inflammation of the eyelids characterized by a scaly crust on the lid margins. The condition may be caused by a bacterial infection, or it may be allergic in origin or associated with seborrhea of the face and scalp. Treatment usually involves cleansing the eyelids on a regular basis to remove excess oil, debris, and desquamated skin that may be problematic.
Often associated with or secondary to blepharitis is a bacterial infection of the surface of the skin at the edge of the lid, known as an internal hordeolum. Other such infections include external hordeolum, commonly referred to styes, which are infections of the tiny oil secreting meibomian glands along the edge of the eyelid, surrounding the eyelashes. A stye begins as a red, tender bump and usually fully develops within three days. Such conditions are accompanied by pain, redness and tenderness of the lid margins. Although styes are often recurring, regular cleansing of the eyelid margins can minimize such conditions. A second problem is a chalazion, which is an inflammation of the meibomian glands inside the eyelid. Chalazia typically grow slowly over 2-3 weeks and although they do not typically cause pain, they often require surgical intervention if left untreated.
With any of the above-described problems, as well as other medical complications, such as rosacea and seborrhea, proper eyelid hygiene with the use of an eyelid cleanser may minimize the severity of the outbreak, or prevent the problem altogether if caught early. Eyelid cleansers are also used for cleaning eyelashes, eyelids or the periocular area and may be used as a pre-operative scrub to help reduce the presence of harmful bacteria which may cause infection, inflammation, or even endophthalmitis in patients.
Endophthalmitis is an intraocular infection that commonly occurs after cataract surgery. The causative agent in post-operative endopthalmitis is typically a bacteria, often the causative bacteria is Staphylococcus Epidermidis. To prevent post-operative endopthalmitis as well as blepharitis, an eyelid scrub is often used to cleanse the eyelid.
Often simple skin cleansers are unsuited for use on the eyelid. Eyelid cleansers must be non-irritating to both the sensitive skin around the eye and the eye tissue itself, while having an antimicrobial effect. One factor causing eye irritation is an abnormal pH level of the eyelid cleaner composition. Non-irritating formulations should have a pH level which is close to neutral, 7.0. Many skin cleaners have a pH outside this range. To control the pH level of skin cleanser a traditional pH adjuster is often employed. Traditional pH adjusters include basic pH adjusters, such as ammonia, mono-, di- and tri-alkyl amines, mono-, di- and tri-alkanolamines, alkali metal and alkaline earth metal hydroxides (e.g., ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, monoethanolamine, triethylamine, isopropylamine, diethanolamine and triethanolamine), and acidic pH adjusters, such as mineral acids and polycarboxylic acids (e.g., hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, citric acid, glycolic acid, and lactic acid). Unfortunately, pH adjusters can also cause eye irritation themselves. Therefore, there is a need for an eyelid scrub composition which is effective at killing bacteria, but does not include traditional pH adjusters, so that it is gentle enough to be used around the eye.